This invention relates to a mobile station and a mobile radio communication network, such as a mobile telephone system.
A conventional mobile telephone system comprises a base station and a plurality of mobile stations. The base station is situated at a fixed location and has a service area. Each mobile station is installed in an automobile or a like vehicle. The mobile station is for use by a subscriber or user who is driving the automobile in the service area.
The base station is for transmitting a radio frequency communication signal towards one of the mobile stations that is selected as a selected station. The communication signal comprises a down-loop indicating signal and, an intermittent succession of call signals. The down-loop indicating signal is for specifying the selected station. The call signal succession is for making the selected station notify the subscriber of a call from the base station.
Each mobile station includes a transmitter, a receiver, and a power supplying circuit. The transmitter and the receiver are for transmitting and receiving communication signals between the base station and the mobile station. The power supplying circuit is for supplying electric power from a battery to each of the receiver and the transmitter.
When the down-loop indicating signal is monitored by the receiver, a down-loop check signal is produced in the selected station. In response to the down-loop check signal, the transmitter is supplied with the electric power to transmit a specific up-loop signal towards the base station. Thus, the base station is operatively coupled to the selected station through a selected one of radio communication channels.
In a conventional mobile station, the transmitter is continuously supplied with the electric power after transmission of the specific up-loop signal even if it is unnecessary to transmit the communication signal from the transmitter. As a result, the conventional mobile telephone system is disadvantageous in that the selected mobile station uselessly consumes a great amount of electric power.
In view of the above, the power supplying circuit may temporarily be disabled after transmission of the specific up-loop signal. This, however, results in a reduction of an activity ratio of the radio communication channels as will later be discussed.